Wouldn't it be easier to just read a Choose Your Own Adventure, or play a solo text based adventure game? Or just log on to a roleplaying leaning MUD and still get the benefit of others?
The boundaries have always been fuzzy between RPGs that are a "social experience" and ones that are not. "Social experience" isn't necessarily a part of the definition of what an RPG is, even if you restrict it to just table top RPGs and not the equally long history of CYOA RPGs and Computer RPGs.
Between indie developers on sites like itch.io and elsewhere there's been a lot of interesting exploration of solo RPG adaptation (playing existing RPGs with their sometimes decades of lore and tools) and new solo RPG development. Which yes, to partially answer your questions: an RPG designed for a solo experience is likely always "easier" to play than playing an RPG designed for a table full of people, especially if you have to also do the work adapting it for solo play. (That said, again, there's an interesting growing market for "professional" solo adaptations of well loved table-top settings.)
Someone who enjoys solo role playing would probably enjoy role playing with others.
Why is solo role playing any different than playing a video game alone?
Hell, there are games like Microscope that would be incredibly fun playing solo.
That's valid, I guess I never really thought of them that way.
In the middle era, the trend was obvious with games like Vampire: The Masquerade and its Storyteller system, coupled with the LARPing fad and some diceless games.
Since that era, the trend has continued. Many games now have little or no crunch at all, and focus almost entirely on world-building, storytelling, and improv. Some games, like the mentioned Microscope, along with Ex Novo and The Quiet Year are almost entirely crunchless world-building and storytelling.
You can go quite far with just oracles and no system at all, and then if you need one, easily pull in something modern and light like FATE, Mythic, or Fu RPG that just adds a few die rolls to your otherwise creative campaign.
And it can be more soloable than crunchy games because you don't need tons of rules and stats and dice rolls. You instead have creative prompts and oracles and source material and can just go with it, reading, interpreting, writing wherever your imagination takes you.
I did also do a lot of solo wargaming, so crunch is not un-soloable, but less crunch is easier and can feel more rewarding.